1. Field of the Invention
The present invention relates to a multi-output power supply apparatus for resolving a power imbalance between multiple outputs in the case of a simultaneous occurrence of an excessively light load and an overload.
2. Description of the Related Art
Power supply apparatuses have been widely used in commercially-used electronic devices, and the like, as well as in information technology devices such as personal computers, and the like, and home appliances such as air-conditioners, audio systems, visual display devices, and the like.
The power supply apparatuses may provide a plurality of output voltages depending on the electronic devices to which the power supply apparatuses are applied.
A general multi-output power source supply device converts input DC power into AC power through a transformer and then rectifies the converted AC power, respectively, to output a plurality of DC voltages.
However, the general multi-output power source supply device has a problem in that when a voltage level of a single DC voltage, among the plurality of DC voltages, is changed by the transformer, the remaining DC voltages are affected so cross-regulation is not maintained.
To solve this problem, a multi-output power supply apparatus employing a step-down chopper circuit (or a buck chopper circuit) in an output terminal thereof has been used.
The step-down chopper circuit may include a switch, a free-wheeling diode, and a filter.
Thus, the general multi-output power supply apparatus has a problem in that re-conversion of power by the step-down chopper circuit after primary power conversion degrades power conversion efficiency and the presence of the step-down chopper circuit increases the number of components, resulting in an increase in fabrication costs.
In order to solve the problem, a multi-output power supply apparatus, like that of the related art document below, that controls switching of an output terminal upon being synchronized with a switching terminal of a power conversion terminal is known
However, in the multi-output power supply apparatus, a power imbalance among multiple output voltages may occur due to an imbalance in a switching duty ratio in the occurrence of an excessively light load or overload.